We have 5 players and they took out the final encounter in Sunless Citadel fairly easily. Note, they aren't experienced players either. If you manage to make it to the end with your 7 players I'd suggest adding a couple more significant enemies in there.
The additional content is probably there to make a distinction between LMoP and Shattered Obelisk. Plus it adds things to surprise players who have already run through LMoP. I dunno, I haven't gotten it yet so I could be off base.
Storm King's Thunder 23
Tomb of Annihilation 24 + 1 = 25
Waterdeep: Dungeon of the Mad Mage 10 - 2 = 8
The Wild Beyond the Witchlight 29
Tales from the Yawning Portal 38
Ghosts of Saltmarsh 41
Light of Xaryxis 22